Telephone system with flickering recall



H. D. CURRIER.

TELEPHONE SYSTEM WITH FLICKERING RECALL.

APPLICATION FILED SEPT. I 9, I914.

Patented Dec. 12,1922.-

IYZJEZYEZT 155F527? EEUJ'FZPJT Patented Dec. 12, 19 22 HIRAM D. CURRIER, OF CHICAGO, ILLINOIS, ASSIGNOR TO KELLOGG SWITCHBOARD & SUPEPLY COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

TELEPHONE SYSTEM WITH FLICKERING RECALL.

Application filed September 19, 1914. Serial No. 862,463.

To all whom it may camera.

Be it known that I, HIRAM D. Come, a, citizen of the United States of America, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Telephone Systems with Flickering Recall, of which the following is a specification.

My invention relates to telephone systems and has for its object the provision of new and improved facilities for attracting the attention of the operator at an exchange should a subscriber desire the attention of the operator.

My invention in one embodiment for instance contem lates the provision of means whereby shou d a connected subscriber desire the attention of the operator, one movement of the switch hook under the control of said subscriber is sufiicient to start in operation certain instrumentalities which convey to the operator an intermittent signal similar for instance to the signal which might be brought to the attention of the operator by the repeated flashing of the switch hook.

This particular form of the invention may be carried outby the use of an interrupter which after the switch hook of aconnected line has been moved once, is placed in circuit to flash the clearing out lamp associated with the cord circuit so as to more readily attract the attention of the operator. I

I will explain this particular form of carrying out my invention more in detail by referring to the accompanying drawing illustrating a telephone system diagrammatically to which my improved circuit arrangements have been applied. The circuit disclosed in this illustration while not one of the most the line relay 6. The operator at the central station noting the lighted line lamp 4 thereupon inserts the plug 7 into the jack 8, thereby'energizing link circuit relays 9 and 10, the circuit of relay 9 being traced from battery through winding of said relay 9, tip contacts of the connected plug and jack to ground through the winding of coil 5. The circuit of relay 10 may be traced from battery through the winding of said relay 10 sleeve contacts of the connected plug and jack, through the closed contacts at the substation switch-hook and; to ground through the winding of coil 5. The insertion of plug 7 into jack 8 opens the contact 13 of the ack bringing about the de-ene'rgization of line relay 6 thus effacing the line signal 4. It may be here pointed out that the jack spring 11 is adapted for association with the tip of the plug 7, and the springs 12 and 13 are adapted for association with the sleeve of the plug 7. The closing of alternate contacts 40 and 41 of relay 9 connects the operators set 0 to the cord conductors enabling the operator to enquire the wants of the calling subscriber. The operator thereupon tests the called line, which in this instance is, assumed to be the line connected with sub station B, and upon finding it idle inserts the plug 14 into the jack of the called line. The insertion of the plug 14 o crates the relay 15 whose circuit can e traced from the ground at 16 through winding of coil 24, tip contacts of the connected plug and jack, the winding 17 of the relay 15, spring 18, conductor 19, coil 20 and through battery 21 to ground. "I'hereupon the relay 15 is locked up, the locking circuit from said relay being traced from ground at 22, through battery, through the winding 23 of said relay, alternate contact springs 18, winding 17 of said relay, tip' of the plug 14, through coil 24 and to ground at 16. The

opening oi normal contacts 56" and 57 of relay 15 upon its actuation disconnectsaheoperators set 0 from the cord conductors pre- 42 the closed contact 27 of the end springs,

normal contact 43 of relay 25, normal contact 36 ofrelay 31 and to ound at alternate contact 26 of relay 15. ete-r relay 42 closes its alternate contact 44 to energize meter magnet 45 to operate the meter 28 once. Af-

. relay 29 at contact 46, the said relay 25 caus- Y ter the initial actuation of the relay 25, it is locked in its energized condition by Way ,of its alternate contact 43, normal contact 36 of relay 31, to the grounded spring 26 of relay 15. The operation of the relay 25 closes its alternate contact 46 to establish an energizing circuit for interrupter relay 29 traced from battery through the winding of the said relay 29, alternate contact 46 of relay 25 to ground at interrupter 30. The relay 29 is thus intermittently energized and de-energized by the interrupter 30 to connect and disconnect ringing conductor 47 to alternate contact48 of relay 29, thereby maintaining an interrupter ringing circuit for the called substation B. The response of the subscriber at the station B causes the actuation of relay 31, over a circuit traced from battery through the winding of the said relay 31, normal contact 48- of relay 29 (when said relay is in its de-energized-position) sleeve contacts ofthe connected plug and jack, the now closed contacts of the switch-hook at the substation B to ground through the winding of coil 24. The opening of normal contact 36 of relay 31 opens the circuit of the relay 25. The relay 25,

upon restoration, opens the circuit of the ing the relay 29 to restore, thus disconnect ing the ringing lead 47 from the tipconductor of the cord circuit C.

After the completion of the conversation, the restoration of the receiver at the station 18 permits restoration of the relay 31, due to the opening of the switch-hook contacts. The restoration of relay 31' closes an energizing circuit for supervisory lamp 32 traced from battery through the pilot relay, lamp 32, normal contact 43 of relay 25, normal contact 36 of relay 31 to ground at alternate contact 26 of relay 15, thereby lighting the supervisory lamp 32. Upon the restoration of the receiver at the station A, relay 33 is actuated on account of the restoration of the relay 10 due to the opening of the switch-hook contacts at the substation, the

circuit for the relay 33 being traced from battery through the winding of said relay 33, normal contact 50 of relay 10, alternate Contact 51 of relay 9 (relay 9 remaining'energized as long as the plug 7 remains in the jack 8) to ground at alternate contact 26. Due to the energization of relay 33 its alternate contact 52 is closed thereby lighting the supervisory lamp 34 over a circuit traced from battery through the pilot relay, supervisory lamp 34, alternate contact 52 of relay 33 to ground at normal contact 53 of relay 35. The relay 33 thereupon is locked in its energized condition over a circuit traced from battery through the winding of said relay 33, its alternate contact 54 to the grounded spring 26 of relay 15. The operatornoting the two lighted supervisory signals 32 and 34 knows that conversation has terminated and removes the plugs from the connected jacks opening the circuit of relays 9, 15 and 33. Relay 15 restoring opens the energizing locking circuit for relay 33 at contact 26 allowing. the said relay 33 to restore. Theapparatus of the cord circuit is now at normal and available for establishing other connections. Assuming now that the subscriber at the station A wishes to recall, before the operator 35, alternate contact 50 of relay 10, alternate contact 51 'to ground at alternate contact 26. The actuation of the relay 35 completes a circuit from the interrupter 3O through the clearing out lamp 34, traced from battery through, the pilot relay, the lamp 34, alternate contact 52, of relay 33, alternate contact 53 of relay 35 to ground at interrupter 30, thus intermittently lighting and extinguishing this lamp 34 to convey a positive signal to the operator that the substation A. is desirous of recalling. The operator in re-establishing another connection with another called'line with the plu 14 removes the plug 14 from the previous y connected jack and the withdrawal of the plug 14 then restores relay 15 opening the alternate contact 26 to break the ground connection at spring 26 to thereby restore relays 33 and 35. The withdrawal of the plug 14 to re-establish another connection withanother line brings about circuit changes in the cord circuit C as previously described in connection with the called substation B, and further description is not necessary. From this specific description of one form of the invention its nature will undoubtedly be clear to those skilled in the art, and it will also be clear that changes and modifications herein can be readily made without departing from the spirit of my invention.

' plurality of circuits for said lamp, means responsive to an operation of said substation switch to close one of said circuits thereby'causing said supervisory lamp to. glow continuously, and means responsive to a single subsequent operation of said substation switch to close another of said circuits thereby causing said supervisory lamp to be intermittently operated.

2. In a telephone system the combination with a telephone line and a substation switch for controlling the circuit thereof, a supervisory lamp located at a central exchange, a plurality of circuits for said lamp, means responsive to an operation of said substation switch to close one ofsaid circuits thereby causing said supervisory lamp to glow .tion.

3. In a telephone system the combination with a telephone line and a substation switch for controlling its circuit, of a signal'located at a central exchange, means including a supervisory relay controlled by an operation of said substation switch to cause a continual actuation of said signal, and means controlled by a subsequent single actuation of said substation switch to cause an intermittent operation of said signal, said last means comprising an' interrupter and a circuit changing relay for controlling its association with said signal, the circuit of the coil of said circuit changing relay being com pleted thru normally open contacts of said supervisory relay.

4. A telephone system comprising a sub- .scribers telephone line, a substation switch for bridging a transmitter across said telephone line, a signal located at the central exchange but under substation control, a re lay adapted to be operated responsive to the opening of said bridged circuit to close a continuouslyoperating circuit for said signal, and a Second relay responsive to the closure of said bridged circuit-to switch said signal to a periodically operating circuit.

5. A telephone system comprising a' sub scribers line, a link circuit provided with a terminal for connecting said line with said link circuit, a signal for said link circuit, a supervisory relay in the link circuit responsive to the replacement of the receiver at the subscribers substation for causing a a continual operation of said signal, and a circuit changing relay responsive to a second energization of said supervisory relay to cause a periodic operation of said signal.

6. A telephone system comprising a subscribers telephone line, a supervisory sig nal located at a central exchange, a substation switch for conductively uniting and disuniting the line limbs of said telephone line,

a relay responsive to the opening of said line by said switch to close a continuously operating circuit for said signal, and a second relay responsive to a subsequent closure of said line by said switch to switch said signal to an intermittently operating circuit.

7. In a telephone system the combination with a cord circuit, of a subscriber controlled supervisory relay, a locking relay, an operators listening switch having auxiliary contacts, an operating circuit for said locking relay, extending thru said auxiliary contacts of said listening switch, a locking circuit for said relay independent of'the auxiliary contacts of said listening switch, and a fiashingrecall signalcontrolled by said locking relay and said superviso relay, whereby the recall signal is displayed upon the second energization of said supervisory relay, and a disconnect signal is displayed upon the first de-energization of said supervisor relay.

8. A te ephone system including a subscribers line, a cord circuit for connection thereto, a supervisory relay, a supervisory signal, a second relay adapted to follow the operations of said supervisory relay after said supervisory relay has been once energized and de-energized, and circuit means for said supervisory signal controlled by said second relay to cause a continuous operation'of said supervisory signal to denote a disconnect, and an intermittent operation of said supervisory signal to denote a recall.

9. In a recall indicating telephone system, a cord circuit, an operators circuit, a listening switch, a pair of auxiliary contacts on said listening switch, a supervisory signal, an automatic circuit interrupter, a looking relay having 'its initial operating-- circuit passing through said auxiliary contacts and contacts-of said locking relay in the circuit of said interrupterand said si nal.

10. In a telephone system t e combination with atelephone line, of a cord circuit for connection with said line, an operators circuit for connection with the cord circuit, a switch for connecting the operators circuit with the cord circuit, a pair of auxiliary operators switch contacts, an answering supervisory signal subject to two different ditions for said signal, a supervisory relay.

having its circuit extending through contacts of said plugand jack, controlling the operative condition of said first relay, the

, initial operating circuit for said firstrelay being local to the cord circuit.

'12. In a telephone system the combination with atelephone line terminating in a jack at the central oflice, a cord circuit terminating in a plug, a supervisory signal, means to display said signal in two different ways to indicate either a disconnect or a recall, a relay controlling the different dis-- play conditions for said signal, a supervisory relay having its circuit extending through contacts of said plug and jack, controllin the operative condition of said first relay tie initial operating circuit for said first relay being individual to the cord circuit.

13. In a telephone system the combina tion with a telephone lineterminating in a jack at the central oifice, a cord circuit terminating in a plug, a supervisory signal,

means to display said signal in two different ways to indicate either a disconnect or a re call, a relay controlling the different display conditions for said signal, a supervisory relay having its circuit extending through contacts of said plug and jack, controlling the operative condition of said first relay, the initial operating circuit for said first relay being independent of contacts of the plug and jack.

14. In' a telephone system the combination with a telephone line and a link circuit connected thereto, of a signal for the link circuit having two display indications, one for a disconnect and the other for a recall, and a locking relay for use in controlling the character of the display of said signal, both the actuating and the holding circuits for said locking relay being independent of conductors individual to said telephone line.

15-. In a telephone system the combination with a telephone line and an exchange, and a link circuit connected to said line, of a signal for the link circuit having two display indications, one for a disconnect and the other for a recall; a, locking relay for use in controlling the character of the display of said signal, both the actuating and the holding circuit for said locking relay being local to the exchange and a normally open listening switch contact in the circuit of said lockin relay.

16. n a telephone system the combination with a telephone line and a link circuit connected thereto, of. a signal for the link circuit having two display indications, one for a disconnect and the other for a recall, and a locking relay and an auxiliary relay for use in controlling the character of the display of said signal, both the actuating and the holding circuit for said locking relay being individual to said link circuit.

17. In a telephone system the combination with a telephone line and a link circuit connected thereto, of a signal for the link circuit having two display indications, one for a disconnect and the other for a recall,'a locking relay for use in controlling the character of the display of said signal, the locking circuit for said locking relay being independent of the line conductors of the telephone line, and an auxiliary relay controlled by said locking relay.

18. In a telephone system including an exchange, the combination with a telephone line and a link circuit connected thereto, of a signal for the link circuit having two display indications, one for a disconnect and the other for a recall, a relay for controlling the character of the display of said signal,

and a locking relay controllingsaid' first relay, the locking circuit for said locking relay being individual to said telephone exchange. 19. In a central telephone exchange system the combination with a telephone line and a link circuit connected thereto, of a signal for the link circuit having two display in'- dications, one. for a disconnect and the other for a recall, a relay for controlling the character of the display of said signal, and a supervisory relay and a locking relay for controlling said first relay, the actuating circuit for said locking relay being local to the central exchange.

20. In a telephone system the combination with a cord circuit, of an interrupter mechanism, a locking relay, a subscriber controlled supervisory relay, an operators listening switch, a pair of normally open auxiliary contacts for said, listening switch, a supervisory signal, an interrupter mechanism, said locking relay controlling the efcircuits for said signal having means therein providing two different display indications, a switching relay having normal contacts for completing the circuit for said signal when one indication is desired, and abnormal contacts for completing the circuit of said signal when the other indication is desired, and a subscriber operated relay having a pair of normally open contacts desired, and a subscriber operated relay hav-' ing a pair of contacts closed upon the energization of said relay, which, when opened, may interrupt an energizing circuit for said switching relay.

23. In a telephone system the COIIlblIlfl'.

' second of said relays, a pair of energizing circuits for said signal for producing different display indications in said signal means responsive to the first deenergization of said subscriber controlled relay for closing one of the display circuits for said signal, and means" responsive to a subsequent energization of said subscriber controlled relay for closing the other display circuit for said signal.

24. In a telephone system the combination with a telephone line, of a cord circuit for connection therewith, a pair of relays for the cord circuit, one underthe control of the operator and the other under the control of the subscriber on said telephone line, a supervisory signal jointly controlled by said relays, and a third relay jointly controlled by said first relays for determining the character of display of said signal.

25. In a telephone system the combination with a telephone line, of a cord circuit for connection therewith, a pair of relays, and a source of current associated with said cord circuit and adapted to be placed in bridge of said telephone line by the connection of the cord with the line, one of said relays being under the control of the operator and the other of said relays being under the control of the subscriber on said line, a supervisory signal, and a. third relay under the joint' control of said relays and controlling the circuit of said supervisory signal,-so as to provide two different displays, one for indicating a disconnect and the other for indicating a recall.

26. In a telephone exchange system, a telephone line, a link circuit connected therewith, a supervisory relay for the link circuit, a signaling device, an operatingv circuit therefor established upon the de-eiiergization of the supervisory relay, a normally ineffectiveintermittent operating circuit for the signaling, device, a second relay energized upon the de-ener-gization of the supervisoryrelay, and a third relay operating while the supervisory and second relays are energized to render the first.operating circuit ineffective and the second effective.

telephone line, a link circuit connected therewith, a supervisory relay for the link. circuit, a signaling device, an operating circuit therefor established by the de-energization of the supervisory relay, a. second operating circuit for the signallng device, interrupter mechanism in the second operating circuit, and a relay conditioned for operation 'upon the de-energization of the supervisory relay and operated upon the subsequent energization thereof to open the first and close the second operating circuit. 28. In a telephone exchange system, a telephone *line, a link circuit connected therewith, a supervisory relay for the link circuit, a signaling device, an operating circuit therefor established upon the de'-ener gization of the supervisory relay, interrupter mechanism, a relay conditioned for operation upon the de-energization of the supervisory relay and operated upon the subsequent energization thereof, and a second operating circuit for the signaling devlce established upon the operation of the second mentioned relay and including the interrupter mechanism.

29. In a telephone exchange system, a telephone line, a. link circuit connected .27. In a telephone exchange system, a

therewith, a supervisory relay for the link interrupter mechanism in circuit with thesignaling device to cause the intermittent operation thereof.

30. In a telephone exchange system, calling and called subscribers lines, a link circuit connectlng' said lines, a circuit, a s1gnaling device and interrupter mechanism adapted to be serially included in said circuit, and means controlled by the restoration to and thesubsequent removal from its hook of the receiver at the calling station for completing the circuit through the interrupter mechanism and the signaling device.

31. In a telephone exchange system, calling and called subscribers lines, a link circuit connecting said lines, a supervisory relay, a signaling deyice, interrupter mechanism, and a relay conditioned for operation upon the de-energization of the supervisory relay and operated upon the subsequent energizat-ion thereof to connect the interrupter mechanism in circuit with the signaling device.

32. In a telephone exchange system, subscribers lines, a link circuit having one end connected to a subscribers line, a super-' visory relay associated with the link circuit and controlled from a connected substation, a signaling device, interrupter mechanism, a primary relay conditioned for operation upon the connection of the other end of the link circuit with another subscribers line and operated upon the ,de-energization of the supervisory relay, and a secondary relay operated upon the subsequent energization of the supervisory relay to include the interrupter mechanism in circuit with the signaling device.

33. In a telephone exchange system, calling and calledsubscribers lines, a link cir cuit connected with the calling line, a signaling device associated with the link circuit.

interrupter mechanism, a relay conditioned for operation when the link circuit is connected with a .called line and operated upon the restoration. of the receiver to the switchhook by the calling subscriber, and a second relay operated upon the subsequent removal of the receiver from the switch-hook by the calling subscriber for including the interrupter mechanism in circuit with the signaling device.

34. In a telephone exchange system, calling and called subscribers lines, a link circult for connecting the lines, a signaling device individual to and in the link circuit, interrupter mechanism serving when in circuit with the signaling device to cause intermittent operation thereof, and means jointly controlled by the operator in connectin the link circuit with the called line an the restoration toand the subsequent removal from its hookof the receiver at the calling station for including the interrupter mechanism in circuit with the Signaling device.

" 35. In a telephone exchange system. callin and called subscribers lines, a link circuit for interconnecting said lines, recall signaling means gassociated with the answering end of said link circuit, and two relays adapted to oo-operate to cause said recall reserve signaling means to operate to present a signal, one of said relays being actuated during connection of said link with a calling line over a circuit including a portion of a talking strand of said link, and the actuation of said other relay being controlled from the calling substation, said, recall signaling means being conditioned for operation by i the interrupter mechanism, a primary relay energized upon the connection of the'link circuit with one of the lines over a path including a portion of a talking strand of the link circuit, a supervisory relay in the link circuit and controlled over the connected line, and a secondar relay energized when the primary relay is energized and the su-. pervisory relay. is de-energized-to close a break in the operating circuit. the-subsequent energization of the supervisory relay causing the signaling device to operate intermittently.

37. In a telephone exchange system, call ing and called subscribers lines, a link circuit for interconnecting said lines, flashing signaling means associated with the answer-- ing end of said link circuit, a central source of current, and two relays cooperating when energized to'start and continue the operation of said flashing signaling means to present a signal, one of said relays being energized from said source upon the connection of said link with said calling line over a path including a portion of atalking strand of said link circuit. the other of said relays being energized from said source over a path including a portion of said-"link and the calling line.

38. In a telephone exchange system, call ing and called subscribers lines. a two wire link circuit connecting thelines. a supervisory signaling device, interrupter mechanism. a source of current, a supervisory relay controlled from a connected stat-ion and when de-energized connecting the source of current in circuit with the supervisory signaling device to cause continuous operation thereof to furnish a disconnect signal. and a relay operated by the deenergization 'of the supervisory relay to partially associate the signaling device, the interrupter mechanism and the source of current, the subsequentenergization of the supervisory relay causing the completion of said association whereby the supervisory signaling device is caused to operate call signal.

39. In a telephone exchange system, callintermittently to furnish a recludin'g a portion of a talking strand of said link circuit, the other of said relays being energized from said source over a path including a portion of said link andthe calling line, and operator controlled means for eflacing said signal.

40. A telephone system including a subscribers line, a link circuit for connection thereto, an electromagnetic device and a signal for said link circuit, and a relay for said link circuit controlled over said subscribers line for controlling said device and signal, said signal being actuated continuously when disconnection is desired and said device actuated intermittently when a recall is desired. v r v 41. A telephone system including a subscribers telephone line, a link circuit for connection thereto, an electromagnetically operated device for said link circuit, a signal for said link circuit, a relay for said link cirbuit, subscriber controlled means for actuating said relay, means controlled by said relay to cause a continuous operation of said electromagnetically' operated device when disconnection is signaled for andto cause an automatic intermittent operation of said signal when a recall is signaled for.

42. A telephone system including a subscribers telephone line, an operators cord circuit for connection thereto, a relay for said cord circuit controlled over the subscribers line, a supervisory device for said cord circuit, an electromagnetically operated device, and means controlled by said relay when the subscriber signals for disconnection to cause said supervisory device to operate continuously to denote disconnection and for causing an intermittent operation of said electromagnetically operated device to denote a T603110 43. A telephone system including a calling subscribers telephone line, an operators link circuit for connection thereto to extend a connection therefrom, a supervisory relay for said link circuit controlled over said subscribers line, an operatorscircuit, a listening switch for connecting said, operators circuit to said subscribers line, an auxiliary contact for said listening switch, a locking relay having a circuit extending through said auxiliary contact, an answering supervisory signal, an electromagnetically operated device, means controlled by said supervisory relay and said locking relay for causing a continuous operatlon of sald supervisory slgnal to denote a'dlsconnectlon and to cause an intermittent actuation. of said electromagnetically operated device to denote a recall.

44. A telephone system including a subscribers telephone line provided with an answering terminal, a cord circuit provided with an answering terminal forconnection to said line viaisaid line answering terminal, a signal for said cord circuit, means concaus'ing a continuous operation of said signal when disconnection is desired and an intermittent operation of said signal when a recall is desired, operator controlled means for seizing said recall prior to the disconnection of the cord circuit terminal from the. subscribers line terminal, a called subscrib- I ers line, and a signal for indicating when the called subscriber is being signaled.

45. A telephone system including a subscribers telephone line, a link circuit having a manual terminal. for connection to said telephone line, a supervisory device, means associated with said link circuit for causing the supervisory device to operate continuously to furnish a disconnect signal and intermittently to furnish a recall signal, operator controlled means for seizing said recall prior to a disconnection of said link circuit terminal from said subscribers line, a called line,

and a signal for indicatingwhen the called subscriber is being signaled.

46. A telephone system including a calling and a called subscribers line, a link circuit trolled at the subscribers substation for 'means for signaling the called subscriber,

deviceto operate continuously to furnish a I disconnection signal and intermittently to furnish a recall slgnal, and operator controlled means for seizing said recall prior to disconnection of said link circuit 'fromsaid calling subscribers line 47. A telephone system including a subscribers telephone line, a link circuit for connection thereto, a supervisory signalfor saidlink circuit, a relay having a self-locking contact, a supervisory relay controlling a contact in the circuit of said first relay, means controlled by said relays for causing the continuous operation of said supervisory signal to denote a disconnection and an intermittent operation of said signal to. de-

note a recall, said meansincluding an inter- 1 rupter for causing said intermittent operation, and a third relay having a contact in the interrupter lead extending from the-interrupter.

- 48. A telephone system including a subscrib ers telephone line, a link circuit for connecting thereto, a supervisory signal for a winding normally connected to a strand of said link circuit, a supervisory relay, a circuit for said supervisory relay controlled over the subscribers line, and means con trolled by said relays for causing a continuous operation of said supervisory signal to denote a disconnection and an intermittent operation of said supervisory signal to denote a recall.

49. A telephone system including a calling and a called subscribers telephone line, a link circuit for connecting said lines in conversational circuit, recall signaling means associated with the answering end of said link circuit, and two relays adapted to co-operate to cause said recall signalin means to operate to present a signal, one 0 said relays being actuated during connection of said link with a calling line over a circuit including a strand of said link, said relay being normally connected to said strand, the actuation of the other relay being controlled from the calling substation, said recall signaling means being conditioned for operation by the restoration of the calling subscribers receiver to the switch hook and operated by a subsequent removal thereof.

50. A telephone system including a calling subscribers telephone line, a link circuit for connection with said line, flashing signaling means associated with said link circuit, a plural contact plug. two relays cooperating to start and continue the operation of said flashing signaling means to'present-said signal, one of said relays being normally connected to a contact of said plug and provided with a circuit including sai contact, the otherv of said relays being energized over said subscribers telephone line, and a third relay controlled by said second relay, said third relay following the operations of said second relay.

51. A telephone system including a subscribers telephone line, alink circuit connected thereto, a supervisory relay for the I link circuit, a signaling device, means controlled by the de-energizat-ion ofsaid supervisory relay to cause an actuation of said signaling device, interrupter mechanlsm, a

relay conditioned for operation upon the deenergization of the supervlsory relay and operated upon the subsequent energization thereof, and meanscontrolle d by said second relay for associating said interrupter mechanism with said signaling device to cause an intermittent actuation thereof.

52. A telephone exchange system including a calling and a called subscribers line, a linkcircuit connecting said lines, a supervisory relay, a signaling device, interrupter mechanism and arelay conditioned for operation upon the de-energization of the supervisory-relay and operated upon the subse quent energization thereof to associate the interrupter mechanism with said signaling device.

53. lln a telephone exchange system, a calling and a called subscribers line, a link circult for connecting said lines, a signaling device for said link circuit, interrupter mechanism serving when associated with the signaling device to cause an intermittent actuation thereof, and means jointly controlled bythe operator and the restoration to and the subsequent removal of the receiver from its switch hook at the calling substation for associating the interrupter mechanism with the signalin device, said means including a relay conditioned for operation by the deenergization of said supervisory relay and actuated by the subsequent energization of said relay.

54. telephone 'system including a telephone line terminating in a jack at the central oflice, a cord circuit terminating in a plug for connection to said line via said jack, a supervisory signal means to display said signal in two difi'erent ways to indicate either a disconnection or a recall, relay means controlling the difi'erentdisplay conditions of said signal, a supervisory relay having its circuit extending through contacts of said plug and jack and controlled over the telephone line, said supervisory relay exercising a control over said v relay means which includes a relay conditioned for operation by a de-energization of said supervisory relay, the circuits for said relay means being local to the central oflice.

,55. In a telephone system including a central exchange, the combination of a cord circuit connected to a subscribers lme, a slgnal for the cord circuit, an electromagnetically controlled device, a locking relay for controlling the operation of said signal and device, both the actuating and locking circuits for said locking relay being local to the central exchange, and means controlled by said locking relay for actuating said supervisory signal to indicate a disconnect-ion and to actuate said device to indicate a recall.

56. lln a telephone system the combination with a telephone line and a link circuit connected thereto; of a. signal for the link circuit having two display indications, one for a disconnect and the other for a recall, a locking relay and a second relay for controlling the character of the display of said signal, an actuating and a holding circuit for said locking relay local to the exchange, and a circuit for said second relay conditioned for operation by said locking relay.

57. lln a telephone system the combination with a telephone line and alink circuit connected thereto, of a signal for the link circuit having a recall display ind cation, a locking relay and a second relay for controlling the recall display of said signal,

HID

the locking circuit for said locking relay beingindependent of the line conductors of the telephone line, and a circuit for said second relay conditionedfor operation by said locking relay. v

58. In a telephone system the combination with a telephone line and a link circuit connected thereto, of a signal for the cord circuit having a recall display indication, a

locking relay and a second relay forcontrolling the recall'display of said signal, a supervisory relay controlling a contact in the circuit of said locking relay, said locking relay operating said second relay upon a second energization of said supervisory relay. I

59. Ina telephone system the combination with a telephone line, of a cord circuit for connection therewith, a pair of relays, a source of current associated with said cord circuit and placed in bridge of said telephone line by the connection of the cord with the line, one of said relays being under the control', of the operator and the other of said relays being under the control of the subscriber on said line, a supervisory signal under the joint control of said relays and operating to provide two different displays, one for indicating a disconnect and the other for indicating a recall, and means controlled by the operator for restoring the supervisory signal to normal when it displays a recall.

60. A telephone system including subscribers telephone lines, a cord circuit for interconnecting said lines, a signal for said cord-circuit, a supervisory relay controlled over a connected subscribers line, a locking relay having a circuit controlled by said supervisory relay, a third relay conditioned for operation by said locking relay, and means controlled by said third rela for causing an intermittent operation 0 said signal, said third relay following the operations of said supervisory relay.

61. A telephone system including subscribers telephone lines, a cord circuit for interconnecting said lines, a signal for said cord circuit, a supervisory relay controlled over a connected-subscribersv line, a locking relay having a circuit controlled by said supervisory relay, a third relay conditioned for operation by said locking relay and actuated by a subsequent energization of said supervisory relay, and means set in operationby said third relay for intermittently operating said si al.

62. na telephone system, the combination of a subscribers line circuit connected with a central oflice link circuit, a signal for said link circuit, a substation switch for said line circuit, relay means responsive to an actuation of said substation switch to cause said signal to glow continuously, said relay means of said substation switch to cause an automatic lntermittent operation of said signal, and responsive to a further actuation of said substation switch to again cause a continuous operation of said signal.

63. A telephone system including a subscriber?s line circuit having a substation switch, a link circuit for connection with said line circuit, a signal for said link circuit, relay means for said link circuit responsive to one actuation7of said sub-station switch to cause a continuous actuation of said'signal, responsive to a subsequent actuation of said switch, to cause an automatic intermittent operation of said signal, and responsive to a further actuation of said substation switch to cause a continuous actuation of said signal.

64. A telephone system including a subscribers line circuit having a substation switch, a central office link circuit for connection with said line circuit, a signal for said link circuit, relay means for said link circuit including a relay controlling different displays of said signal, saidrelay means also including a relay responsive to the actuation of said substation switch to cause different actuationsof said first relay, thereby causing different displays of said signal, means rendering said first relay unresponsive to, a first energlzation of said second relay, and. a manually actuated operators switch to render said first relay operable responsive to the second.

65. A telephone system including a subscribers telephone line, a link circuit for connection thereto, a supervisory signal, a relay for causing different displays of said supervisory signal, a relay controlled over the subscribers line circuit for causing different actuations of said first relay, thereby causing the different display indications of said signal and operators listening means to place said first relay under control of the second.

66. A telephone system including a subscribers line circuit, a link circuit for con nection thereto, a signal for said link circuit, a relay for causing a continuous operation of said signal, also for causing a subsequent automatic intermittent operation of said signal, and for causing a subsequent continuous operation of said signal, and a relay controlled over the subscribers line circuit for controlling said first relay.

67. A telephone system including a subscribers line circuit connected with a cen tral oflice link circuit, a signal for said link circuit, a supervisoryv relay controlled over the subscribers line circuit, a second relay unaffected by the first actuation of the said supervisory relay but adapted to follow the subsequent operations of said supervisory relay to cause either a continuous actuation or an automatic intermittent actuation of said signal at the will of the subscriber.

68. A telephone system including a subscribers line circuit connected with a central office link circuit, a signal for said link circuit, a relay controlled over said subscribers line circuit, a locking relay con-i trolled by said first relay, and a third relay controlled by said two relays for causing the continuous operation of said signal to denote a disconnect and an intermittent operation of said signal todenote a recall.

69. A telephone system including a subscribers line circuit connected with a central ofiice link circuit, a signal for said link circuit, a relay controlled over said subscribers line circuit, a locking relay controlled by said first relay, and a third relay controlled by the supervisory relay, and a' third relay adapted to follow the operation of said supervisoryrelay after the actuation of said locking relay, said third relay being operable to cause a continuous operation of said signal to denote a. disconnect and 'an automatic intermittent operation of said signal to denote a recall. 7 71. In a telephone exchange, system, a telephone line, a link circuit connected therewith, a supervisory relay for the link circuit, a signaling device, an operating circuit therefor established by the de-energization of the supervisory relay, another circuit for controlling the device, interrupter mechanism in the other circuit, and a relay conditioned for operation upon the deenergization of the supervisory relay and operated on the subsequent energization thereof to render the second circuit efiective- 72. In .a I telephone system, a telephone line, a link circuit connected therewith, a supervisory relay for thelink circuit, a signaling device, an operating circuit therefor, established upon the de-energization of the supervisory relay, interrupter mechanism, a relay conditioned for operation upon the de-energization of the supervisory relay and actuated upon the subsequent energization thereof, to connect the interrupter mechanism to cause the intermittent operation of said signalin device.

73. In a te ephone exchange system, calling and called subscribers lines, a link circult connecting said lines, a supervisory relay, a signaling device, interrupter mechanism, and a relay conditloned for operation upon the de-energization of the supervisory relay and operated upon the subsequent en ergization thereof to operati'vely associate the interrupter mechanism with said signaling device.

74. In a telephone system, the combination of a line circuit connected with a oencircuit, a second relay, a listening switch,

said second relay initially energized over a circuit including a contact of said switch, a locking circuit for said second relay, and a switch contact of said first relay whereby the locked or unlocked condition of said operations of said signal to denote a recall.

A telephone system includinga sub 76. A telephone system including atelephone line circuit connected with a central oflice link circuit, a relay controlled over said line circuit, a second relay having its operative condition changed responsive. to

de-energization of said first relay, its condition remaining unchanged on re-operation of said relay, contacts for said first two relays, a. third relay and a circuit therefor including said contacts, said third relay responsive .to the l e-operation of said first relay, and an automatically intermittent re call signal controlled by said third relay.

77. Atelephone system including a telephone line and a station thereonconnected with a central oflice link circuit, a' relay controlled. over said line circuit, a second relay unaffected by the first operation of said first relay but adapted to follow the subsequent operations of said first relay, signaling means responsive to saidsecond relay including automatic apparatus for intermittently actuating said means, said automatic apparatus effective on a second energization of said first relay.

Signed by me at Chicago, county of Cook and State of llllinois, in therpre'sence of two witnesses.

HIRAM n. Gunmen.

- Witnesses:

Gnoncn E. MUELIER, M. R. Boomers. 

